Lived and worked NV most of the year and everything else IL.
so if you established and can prove your domicile in NV you should be able to file as a NV resident and IL Nonres and apportion your income based on days WORKING in IL
and IL wont be able to challenge (if they are anything like NY.. expect them to be aggressive about it especially if you didn't change your mailing address, voting and DL etc)
But if you could prove it you should be ok
They dont like people going to tax free states (like your hero and NYS)